Apparatus for removing samples from flowing streams



Aug. 17, 1943. G. o. KIMMELL 2,327,111

APPARATUS FOR REMOVING SAMPLES FROM FLOWING STREAMS Filed July 27, 1940 4 sheets-sheet 1 Aug. 17, 1943- G. o. KIMMELL APPARATUS FOR REMOVNG SAMPLES FROM FLOWING STREAMS Filed July 27, 1940 4 Sheets-Sheel'. 3

INV ENTOR l 60mm/1 0 /mme/l B ATToNEY Aug'. 17, 1943. G. o. KIMMELL 2,327,111

APPARATUS FOR REMOVING SAMPLES FROM FLOWING STREAMS 4 Sheets-Sheet 4 Filed July 27, 1940 INVENTOR @nini/1125.

Patented Aug. 17, 1943 APPARATUS FOR REMOVING SAMPLES FROM FLOWING STREAMS Garman O. Kimmell, Oklahoma City, Okla.

Application July 27, 1940, Serial No. `348,063

(ci. vs -21) i 2 Claims.

This invention relates to an apparatus for removing samples from owing streams, particularly turbulently flowing composite streams such as the flow from high pressure distillate wells. Wells of this character have optimum conditions of operation under which the maximum amount of liquid hydrocarbons may be recovered if the well pressures are properly maintained. 'I'he required pressure varies with the saturation of the reservoir gas with the recoverable constituents. Consequently, it is essential to obtain accurate samples of the flow at selected pressures to y determine the reservoir characteristics and the most desirable above ground conditions for the recovery of the maximum amount of liquid hydrocarbons. A vital factor in making an analysis of a well is' that of obtaining a true representative sample of the well flow at well head pressures.

It is, therefore, the principal object of the present invention to provide an apparatus for obtaining representative samples of the well stream at full well head pressure during :dow thereof.

In accomplishing this and other objects of the invention, as hereinafter pointed out, I have provided improved details of structure, the preferred form of which is illustrated in the accompanying drawings, wherein:

Fig. l is a diagrammatic view of the apparatus used in sampling a well stream' discharged from a producing formation under natural formation pressures or through one of the repressuring methods well known in oil iield practice.

Fig. 2 is an enlarged longitudinal section through the jack for introducing the sampling nozzle into the Well tubing against the Well head pressure.

Fig. 3 is an enlarged cross-section on the line 3 3 of Fig. 2.

Fig. 4 is a detail perspective view, partly in section, of one of the tube gripping slips.

Fig. 5 is a cross-section on the line 5 5 of Fig.' 2.

Fig. 6 is a. cross-section on the line 6 6 of Fig. 2.

Fig. 7 is an enlarged section through the up- Fig. 9 is a detail perspective view, partly in longitudinal section, of oneof the sampling noz-v zles.

Fig. 10 is a similar view of a smaller nozzle.

. Fig. 11 is a cross-section through the spider on the line li-ll of Fig. '1.

Fig. 12 is a detail sectional view through the well tubing and sampling nozzle, showing :dow characteristics through the tubing when the velocity in the nozzle tip is greater than the velocity through the tubing.

Fig. 13 is a similar view showing the flow characteristics when the velocity in the tubing is greater than the flow velocity through the nozzle.

'Fig 14 is a similar view when the velocities are equal.

- Fig. 15 is a graph depicting data obtained during tests of the. flow in an actual well.

Referring more in detail to the drawings:

I designates a head of a Well drilled into a gas producing formation and equipped with a Well tubing 2 which extends through the casing 3 and forms a conductor through which the Well ows into a separator il. Pressure is maintained within the well by means of a casing head -5 to seal the space about the upper end of the casing 3 and tubing 2. The upper end of the tubing is provided with a cross-ritting ii having lateral branches l, at least one of which is connect'ed by a pipe 8 with the liquid and gas separator d under control oi a valve 9.

The separator il is of any conventional design and has a gas outlet connection i@ with la discharge line il equipped with a recording orifice meter l2, whereby rate of flow or the gas component of the well stream is recorded. The lower portion of the separator is equipped with the usual liquid discharge connection i3, having connection with the flow line i4 leading to a storage, indicated at I5.

The terms distillate well or condensate Well are now in good engineering ancllegal use to describe a gas well which yields an essentially colorless product under normal conditions of operation. For this type of Well the :dow comprises a composite stream of hydrocarbon liquid and gas. The present conditions of supply and demand are responsible for the inability of the producer to sell the gas phase from his distillate well.

Under proration rulings, if the producer cannot sell the gas, he is not allowed to waste it for the recovery of the distillate alone. The growing practice is to handle large flows from the well, extracting the distillate therefrom, and

i pumping the unliqueflable components back into the reservoir or producing formation. This practice eliminates waste of saleable gas and allows the extraction of the valuable distillate. Therefore it is extremely desirable to determine the pressures required in obtaining maximum recovery of the profitable liquefiable hydrocarbons, as well as other factors concerning, the most desirable methods of handling the well and controlling production of the formation. In a small scale unit these factors and conditions can be determined accurately and economically. It is lessential to obtain accurate representative samples of the well flow at full well head pressure for use in the small scale unit. In the small scale unit pressures can be varied from fulllowing well head pressure down through the retrograde range.

I have, therefore, provided apparatus to take samples simultaneously with the ow.V This is effected by introducing a sampling tube I6 into the well tubing so that a proportionate part of the flow passes through the sample tubing to a test separator I1 having capacity for determin- 23 has a polygonal-shaped portion 24 adapted to be engaged by a wrench, to turn the neck 22 intoY the threaded opening 2|. Extending upwardly from the portion 24 is a cylindrical shaft-like body 25, having a thread 26 formed thereon for a purpose later described. The jack-screw is further provided with an axial bore 21 continuing through the threadedvneck .22 and of a sizeto slidably pass the sampling tube I6, as shown in Fig. 2. 'I'he upper end of the jack-screw is counterbored, as at 28, to receive a packing element 28 adapted to seal about the tubing. The packing 29 is retained in sealing position by means of a follower 30, having a threaded portion 3| engaged with an internal bore 32 formed in a reduced upward extension 33 of the jack-screw, the upward extension being provided with slots 34, Fig. 6, whereby the extension is adapted Vto be contracted about the threaded body 3| by means of a clamping ring 35. The clamping ring 35 is normally of a vsize to be freely mounted on the Vreduced extension and has laterally extending l ears 36 through which a fastening device, such as a bolt 31, is extended to tighten the ring aboutr relation with respect to the packing. The follower further includes an upper threaded portion 40, carrying a sleeve 4| having a plurality of jaws 42 adapted to grip the sampling tube when tapered portions 43 of the jaws are engaged in the tapered bore 44 of a clamping collar 45 that is sleeved thereover, as best shown in Fig. 2. It is thus obvious that the sampling tube maybe fixed relatively to the jack-screw by causing the slip jaws to grippingly engage the sampling tube.

, Thecollar 45 is ,retained between thrust bearings 46 and 41 carried y.within a bearing housing 48,` having an internally threaded portion 49' en` gagingthe upper threaded, extension 40 of the packing follower. The bearing housing 48 has an annular portion 56 provided with radial sockets 5| to receive a. suitable actuating bar, whereby the bearing housing may be rotated relatively to the packing follower to cause the collar 45 to move downwardly in contacting relation with respect to the slip zjaws 42 to cause the slip jaws to grip the sampling tube when the tube is passed therethrough, as later described.

IRotatable on the threaded jack-screw is a nut 52 fixed Within the lower end of a cage-like housing 53 which extends upwardly over the slips 42 and carries a chuck 54. The nut 52 has radial sockets 55 'registering with openings 56 in the wall of the housing 53 to accommodate handles 51 whereby the housing may be rotated upon the jack-screw.l The housing 53 is of such length to accommodate the bearing housing 48 when the nut is at the lower end of the jack-screw, so

that a cap plate 58 forming the upper end of the housing amply clears the ing housing 48.

The upper chuck includes a body 59 having a threaded neck 60 mounted within a threaded opening 6| of the 'plate 58. 'I'he body 59 also includes an upper threaded periphery 62, carrying a bearing housing 63. Projecting upwardly from the threaded portion 62 is a reduced extension 64 having hooked jaws or slips 65. The jaws are tapered,n asat 66, to receive the 'tapered bore 61 of a contracting collar 68, similar to the collar 45, previously described. The collar 68 is retained within'the bearing housing 63 between thrust bearings 69 and 10. The upper bearing housing also has a portion 1| provided with radially extending handles `12, whereby the bearing housing may be rotated to move the collar 68 to and from contracting relation with respect to the upper end of the bear- 45 jaws or slips.

of the well fluid. However, I have solved this ldimculty throughuse of a nozzle 14, Figs. 1, 7, 9,

10 and 12 to 13 inclusive, having a thin body portion 1 5, the inner surface of which is a perfect cylinder and the outer surface a long slightly tapering cone to form an extremely thin entering edge 16 projecting within the well stream, the edge being of such thickness as to avoid eddy currents and resistance which interfere with taking of representative samples when other conditions are provided for, as later described.

In order to mount the nozzle upon the end of the sampling tube, the sampling ,tube is preferably provided with a reduced threaded neck 11 forming a seating shoulder 18 whereon a socket 16 of the nozzle 14 is threaded as shown in Figs. 12 to 14 inclusive. The interior bore of the nozzle at the edge 16 is determined with extreme accuracy so that the effective area thereof is readily proportional with the eifective cross-sectional area of the well tubing. f

When the well isv flowing critically" or turbulently (not heading), a representative sample oi the iiow can be removed from any point within the sampling section of the tubing as long as the sampling nozzle does not touch or nearly touch the wall of the tubing. Therefore I provide the lower end oi.' the sampling tube with a centering spider that is slidable thereon to an adiusted position with respect to the inlet ot the nozzle so that the spider is located a sufficient distance above the nozzle to avoid interference. with taking of an accurate sample.

In the illustratedinstance, the spider includes a collar 8|, Fig. '7, slidable on the sampling tube y and connected with bow-shaped springs 82 having their upper ends connected to a similar collar 83, the collar 83 having a threaded neck portion 84 terminating in slips 85 having tapered peripheral faces engaged within the tapered bore of a nut 86, the nut St being freely rotatable about the sampling tube and having a threaded portion 8l to engage the threaded portion td of the upper collar 83. Thus when the nut is tightened about the slip portion t5, the upper collar 33 is securelygripped in an adjusted position with respect to the sampling tube it, to retain the inlet of the nozzle in substantial alignment with the axis of the tubing.

I have found that another essentialrequirement in obtaining a representative sample, is that the velocity through the thin body portion l of the nozzle 'ifi be maintained identical with velocity through 'the well tubing 2. This is readily explained by observing Figs. 12 to v11i inclusive. In Fig. 12, the velocity V2 in the nozzle tip is greater than the velocity Vi in the sampling section. Consequently, more material will be drawn into the nozzle tip than would normally pass the section occupied thereby. The extra material entering the nozzle would be taken from a zone, between a hypothetical sampling cylinder b and a hypothetical sampling cone a. A particle of liquid in the denser phase in the zone between the hypothetical sampling cone and the hypothetical sampling cylinder, because o its inertia, wouldtend to break through the hypothetical cone a and by-pass the nozzle as shown by the small arrow. This would cause a loss of the denser phase in the sample and the result would be the recovery of a sample in which the ratio of .the less dense to the dense phase would be too high.

In Fig. 13, the veloctiy V3 ai; the nozzle tip is less than the velocity Vi in the sampling section of the well tubing. In this instance, less material will be drawn into the nozzle tip 3 than would normally pass the section occupied by the 'nozzle tip. The material entering the nozzle would be taken from a zone between a hypothetical sarnpling cylinder c and a hypothetical cone d. A particle of the denser phase in the zone between the hypothetical cone and cylinder, because of its inertiay would tend to break between the hypothetical sampling cone and enter the nozzle 3. As shown by the arrow indicating the path of the denser particle, this would cause a gain ofthe denser phase in the sample and the result would be the recovery of a sample in which the ratio of the less dense phase to the denser phase would be too low.

In Fig. 14, the velocity V| in the nozzle tip is identical to the velocity V in the sampling section of the weh tubing. The same amount of material will be drawn into the nozzle tip as would normally pass the nozzle section occupied by the nozzle tip, because the material entering the nozzle will be taken from a hypothetical-sampling cylinder coinciding with the hypothetical sampling cone and there is no tendency for a part of the denser phase to by-pass or enter a 'ing the gate valves I8.

by screwing the threaded neck 22 thereof within part of the nozzle tip, and a representative sample is removed.

Apparatus is, therefore, provided for controlling velocity through the sampling tube, as now to be described. The test separator I'i is connected with the tubing I6 bygmeans of a pipe 8l.

Associated with the pipe 8l is a preheater 88 and a stabilizer 89 located on the respective sides of a control valve 90. The preheater includes a coil 9|V through which the sample of the well iiuid is circulated, the coil being contained within a housing 92 through which steam or other heating medium is circulated. The stabilizer includes a similar coil 93 contained within a housing 9s through which a cooling medium, such as water, is circulated. The temperature of the sample may thus be regulated by controlling ow of the l heating and cooling medium through the respective housings sothat it is at a desired temperature when admitted into the test separator. The gas content of the sample is discharged from the separator through a. pipe 95 having connection with a coil'96 of an after-heater 98, similar in construction to the preheater 92, previously described. From the coil 96 the gas is discharged through a control valve 99 into a critical ow meter |00, including a chamber i0| equipped with a pressure gauge |02 and a thermometer |03, whereby pressure and temperature within the chamber may be noted and brought to the required values. The chamber |0| has a threaded neck |04 projecting from the discharge end thereof which forms a seat for an lorce disk |05, the disk |05 being retained by a cap |06 threaded on the neck |04. The orice |07 of the disk |05 has a size proportionate to the in-- let of the nozzle, whereby the rate of ilow may be maintained so that the velocity through the nozzle is. equal to the velocity of the well flow passing the exterior of the nozzle. rated liquid is taken from the test separator il through apipe |09 under control of a valve |08.

In using an apparatus constructed as described, the well ilow is shut oil' to the separator by clos- The jack is then applied the threaded bore 2| of the tting 20, the tube |6 being contained within the jack and the nozzle end projecting Within the well tubing, the chucks of the jack being loosened to permit the tube to be slid therethrough so that the nozzle is just above the uppermost valve I8. The jack- 'nut 52 is then moved to the upper end of the lconnrcted'with the preheater and other test equipment, the gate valves i8 are opened so that y the pressure acts directly against the nozzle of the sampling tube, but the slips, of the upper chuck hold the sampling tube in position against pressure of the flowing iiuid which is now being4 l discharged through the pipe 8 into the separator.

The jack-nut 52 is then rotated tov the bottom of' the jack-screw, causing the slips carried there- The sepa-` After the discharge l with to move the nozzle further into the well tubing. When the nut is in its lowermost position, the slips of the lower chuck are tightened about the sampling tube and the slips of the upper chuck are loosened. The sampling tube is then gripped and retained in fixed position relative to the Jack-screw while the jack-nut is being moved to the upper end of the screw. When the .lacknut is at the upp'er end of the screw, the slips of the upper chuck are set in gripping relation with the sampling tube, after which the slips of the lower chuck are loosened so that when the nut 52 is rotated and moved in a downward; direction, the nozzle is carried further into the tubing. This process is continued until the nozzle is in desired position. 'I'he well may ilow in heads upon initial opening of the valve 9, and no attempt is made.to take a sample untilI after the well is iiowing steadily. When the well is ilowing steadily, the pressure and ilow velocity are obtained from the recording orice meter I2 and a proper oriiice plate |05 is selected and applied to the critical iiow meter so that the ilaw through the sampling tube to the test separator approximately equals the velocity flow exteriorly of the nozzle.

'I'he sample data obtained. during actual tests of a well are represented in the graph in Fig. 15. A nl; inch nozzle was examined for its ability to remove a representatve'sample at two rates of iiow from the well; six and eight million standard cubic feet cf separated gas perday. A 5/8 inch nozzle was examinedr at a rate of iiow of four million cubic feet of separated gas per day.

The cubic .centimeters of liquid per cubic foot of gas are indicated by the line of the graph. Under all three conditions, a ratio oi.' liquid to'gas of approximately 17.7 cubick centimeters per cubic foot was obtained in the experimental unit when the ratio of velocities inside and outside the sampling nozzles were equal, but any sampling condition resulting in a deviation of unity ratio of y velocities inside and outside the nozzle tip gave an erroneous indication of the liquid gas ratio, as shown by the chart.

With a truly representative fractional part o1' the well stream available, it is possible to examine the characteristics of a total well stream on a, small scale unit. Because of increased accuracy and convenience of operation of a small scale testing unit, it is possible to take data with a greatly increased rate of speed and at the same time materially improve on accuracy obtained in full scale tests, all this being possible through my improved apparatus for taking truly representative samples, as above described. What I claim and desired to secure by Letters Patent is:

1. In combination with a high pressure oil or gas well tubing flowing a fluid under pressure,

, meansfor taking a sample of the fluid under flow including a sampling tube extending into the tubing, a thin walled sampling nozzle carried by the sampling tube and havinga cylindrical inner bore to pass a sample ilow therethrough and having along tapering outer surface cooperating with the surface of the bore to form an extremely thin entering edge for said nozzle, centering means supporting the tube with the axis of said cylindrical bore and said extremely thin entering edge of the sampling nozzle in substantially coaxial relationl with the tubing whereby a predetermined proportion of the iluid is caused to enter the nozzle, and means connected with the sampling tube for maintaining velocity iiow through the bore of the sampling nozzle proportional to the velocity'ow through the tubing.

2. In combination with a high pressure oilorgas well tubing flowing a fluid under pressure, means for taking a sample ofthe fluid under ilow including a sampling tube extending into the iiow line, a thin walled sampling nozzle carried by the sampling tube and having a cylindrical inner` bore to pass a sample fiow'therethrough and having a long tapering outer surface cooperating with the surface of the bore to form an extremely thin entering edge for said nozzle, centering means supporting the tube with the axis of said cylindrical bore andksaid extremely thin entering edge of the sampling nozzle in substantially coaxial relation with the flow line whereby a predetermined proportion oi' the iluid is caused to enterthe nozzle, and means connected with the sampling tube for regulating the temperature and controlling the volume of the iiuid owing from the sampling tube for maintaining velocity flow through the bore of the sampling nozzle proportional to the velocity iiow through the tubing.

GARMAN O. KIMMELL. 

